Five Keys for Achieving Net Zero Energy Schools

Net Zero Energy Design (NZE) has taken leaps and bounds in the past decade, driven by improvements in materials, construction methods, building science, and the decreasing cost of renewable energy. All of this had made Net Zero Energy and Net Zero Ready buildings a viable and affordable goal for Schools.

This, combined with the growing understanding of the impacts of human driven climate change, movements of students across the world demanding climate action, and improvements in state and local energy codes, has many School districts asking if this is the right move for them.

Whether you are building new or renovating an older facility, following these key strategies will put your facility design on the path to creating an NZE school.

1.??????? Reduce Energy Demand: When aiming for an NZE School, the first step is a highly insulated and air-tight building enclosure. The performance of the building can only be as good as the envelope. Trying to reach NZE with typical construction methods is like trying to cross the ocean on a leaky ship. It can be done, but you’re going to spend a lot of time and energy bailing water out that you could have spent elsewhere.

Incorporating high-performance air barriers, increased insulation and triple glazed window systems greatly reduce the heating and cooling demand which, in turn, allows you to use smaller HVAC systems. For example, cost data across a range of projects in Massachusetts shows that the upfront cost associated with these improvements is largely offset by the reduced cost of building mechanical systems.

These improvements are the hardest to retrofit and should be your first priority when thinking about long-term energy reduction.

2.??????? Capture “Free” Energy: Building design strategies should focus on capturing the “free” energy provided by the Sun and prevailing winds. This sounds obvious but you would be surprised how often this is overlooked.

Sustainable buildings use passive solar and passive cooling strategies to maximize the amount of energy captured and minimize the demand on the mechanical heating, cooling, and ventilation systems. This conversation starts with the windows, where more daylight means less reliance on artificial light and heating, reducing demand for electricity.

The number of windows needs to be balanced against opaque facades. Well-insulated walls offer far better thermal performance than even the best triple-glazed windows. Our data shows that, for K-12 schools, the optimum window-to-wall ration falls between 20% and 30%.

3.??????? Efficient System Design: Steps one and two are about reducing the overall energy load of the building. The next step is to maximize these benefits through efficient lighting, HVAC equipment, and appliances. Demand Control Ventilation (DCV) and Energy Recovery Ventilation (ERV) are both energy efficient methods of optimizing indoor air quality in an energy-efficient way and should be leveraged as part of any Net Zero School design.

DCV works by increasing or decreasing the fresh air supply based on the demand for ventilation determined by CO2 sensors. The system can turn the ventilation down during unoccupied hours to the code minimum resulting in significant energy savings.

ERV works by recovering energy from exhaust air so that the energy you have already put into heating and cooling is not “thrown away” when air is removed from the building. High Performance ERV systems can provide up to 80% or more energy recovery resulting in additional energy savings.

Sensor-based Daylight Harvesting systems gauge the level of natural daylight in different parts of the building, automatically dimming the lighting when it is not needed. In the northern hemisphere careful placement of these sensors helps to maximize energy gains in the west, south, and east-facing parts of the building.

Occupancy sensors are another system worth considering. These work by dimming or turning off lights when a space is not in use.

4.??????? Coordination, Commissioning & Construction: Even the best design will fail to reach NZE if not properly installed. As envelopes and HVAC systems grow more complex and inter-dependent, the role of good coordination and commissioning has become more important. It is critical that design teams engage with their engineers and commissioning agent early to ensure proper coordination throughout the design process.

The final component of this is a contractor familiar with the systems and construction methods. Design is national, construction is local. While our team can leverage our national experience, the system will only be as good as the installer. It is important to establish strict performance and testing standards in our specifications and meet frequently with the Contractor to ensure follow-through.

Blower door tests, performed at both the mid-point and completion of the exterior envelope, ensure that air-tightness goals are met. Commissioning of envelope and HVAC systems ensures that all the systems are functioning properly.

Studies show that proper building commissioning can save between 5% and 15% of a building’s total energy usage and are critical to ensuring that you are maximizing the benefits of the first three steps.

5.??????? Renewable Energy: If you’ve successfully incorporated the first four steps, congratulations! You can officially call your project “Net Zero Ready”. To bring the project across the finish line and reach the goal of Net Zero Energy, however, you must connect the building to an onsite renewable energy system of at least an equal energy-generating capacity to how much energy your building uses.

The most cost-effective and feasible option for most school projects is solar Photovoltaic (PV) systems. PV systems are often interconnected with the local utility grid or combined with a commercial-scale electric battery that stores excess energy to meet peak demand.

Many budget-conscious communities are opting to build Net-Zero ready schools, in most cases leaving out the cost of the solar PV from the project budget and choosing to enter into a power-purchase agreement (PPA) in which a third-party installs, owns, and operates the PV system.

In conclusion, Net Zero Energy buildings that were once thought of as a luxury, are now becoming a reality all across the country. With up-front costs coming down and pay-back periods shortening, these buildings are a financially responsible way to reduce our carbon emissions, meet climate goals, and give students a greater appreciation of their role in reducing emissions.

About the author.

Eric Haggstrom , AIA, LEED AP, Fitwel Ambassador, is an accomplished Architect with 15 years of experience in projects including civic, higher education, healthcare, and K-12 education. A seasoned professional with experience on innovative and award-winning projects, Eric was named JCJ ARCHITECTURE ’s Director of Sustainability in 2024. Working to build on JCJ’s long-standing commitment to sustainability, Eric works across regions and project types to optimize integration of sustainable practices and to explore new practice approaches and technologies.